Oracle11g R2 - Edition Based Redefinition for On Line Application Upgrade

Continuous database application evolution with Oracle RDBMS 11gR2 Editions
Performing an application upgrade with new versions of tables, views and packages without suffering any downtime. That is the objective of the Editions feature in Oracle RDBMS 11g Release 2. This presentations illustrates how database development can be organized using Edition Based Redefinition to allow various users and user communities to simultaneously work with different versions of database objects. It will show how to gracefully migrate users and client applications one by one to the latest versions of the database objects, without loss of availability.

5.
Restructuring A12
• Build new road next to current one (A12-B)
– Same “functionality” as
the old road
• At the cut-over moment
– Open new A12-B:
• Newly arriving traffic
travels on temporary road
– Close A12 (original)
• Cars already on old road keep going

6.
Edition Based Redefinition is similar
Application Upgrade:
• Prepare new release
– Construct the release in parallel to the existing
– Operations in existing application ‘edition’
continue normally
• From the cut-over point:
– Have new sessions operate on new release
– Existing sessions can continue to run on existing
release

12.
Some Rules for EBR
(Edition Based Redefinition)
• Editioning acts on packages, functions, triggers,
procedures, views, types and synonyms
• Editioning does not apply to tables
– Data is not versionend, cloned, migrated
– Different incarnations of a table are suggested
through editionable views – there is only one table
• Applications should never access tables directly!
• Cross Edition Triggers on the table synchronize DML from
different editions with the current state of the table
• CET are temporary objects – not part of the application

13.
But wait, there is more
• After the release of a new edition –
there is no reason why you cannot
keep the previous one going for some time
– And multiple previous ones!
• That means – END OF THE BIG BANG upgrade!
– Multiple versions of the application can continue
running to suport various user groups (e.g. SaaS)
• Without data migration and additional downtime upon
later move over of user groups

20.
Summary
Edition Based Redefiniton
• 11gR2 Editions are parallel, co-existing
universes with incarnations of database objects
– The new release can be constructed, tested and run
in a new edition
– The old edition can be switched off at cut-over
• Editions also allow long time co-existence of
multiple releases of an application
• Application Upgrade no longer needs to disrupt
the operation through planned downtime

21.
Conclusion
• See http://www.amis.nl
– To do an 11gR2 PoC together with us
– To learn about 11gR2 training (DBA & Developer)
– For more on database migration services
• Free Event: 29th September – technical details
on 11gR2 including hands-on session
• See Blog for 11gR2 articles
– http://technology.amis.nl/blog
• Contact me: lucas.jellema@amis.nl